Steam generator



J. BLIZARD STEAM GENERATOR Filed y 1938 Q Q Q 3 heets-Sheet 1 INVENTORJOHN BL/ZA/PD ATTORNEY 1 Sept. 26, 1944. BUZARD 7 2,358,785

STEAM GENERATOR Filed May 9, 1938 3 Sheets-Sheet 2 INVENTOR f0f/A/ 54/Z/4 73 ATTORNEY Patented Sept. 26,

' UNITED STATES PATENT OFFICE STEAM GENERATOR Application May 9, 193a,Serial No. 206,737

Claims.

' and efliciently produce saturated steam and simultaneously to producesuperheated steam at all ratings of the steam generating section and atthe desired degrees of superheat up to maxi-' mum superheat at allratings. The arrangements are extremely compact and they areparticularly well adapted to marine installations but they are also welladapted to land installations of every description.

This application is a continuation-in-part of my application Serial No.35,279, filed August 8, 1935.

The nature of the invention, its several features and advantages, willbe understood from the following description when considered inconnection with the accompanying drawings, forming a part thereof, andin which:

Fig. l is a more or less diagrammatic illustration. in partial verticalsection, of a steam generator marine installation embodying theinvention;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a vertical sectional view through an air casing at the frontof a steam generating section embodying the invention;

Fig. 4 is a horizontal sectional view on line t-l of Fig. 3, and

Fig. 5 is a sectional view showing the operating means for the dampersdisclosed in Figs. 3 and 4.

Like characters of reference refer to the same or to similar partsthroughout the several views.

Referring to Figs. 1 and 2 of the drawings, reference character l0designates the hull of a ship having a deck I I. In the particulararrangement illustrated in Fig. l, two'generating units are disposedtransversely of the longitudinal axis of the ship and back to back. Anynumber of pairs of such units may be utilized in a ship or any number ofsingle units may be used in either a marine or stationary environment.The steam generating unit includes a setting l2 having asteam and waterdrum IS in the upper part of the setting, and two spaced water drums IIand ii in the lower part of the setting. A main bank of steam generatingtubes 16, which may for convenience but without limiting effect hereferred to as a first bank, connects the drums I 3 and I5, and a bank,or screen, of suitable spaced steam. generating tubes I! which may bereferred to without limiting effect as a second bank connects the drumsl3 and H. The tubes of the bank I! may be arranged as shown in Figs. 1and 2 in a plurality of parallel rows with the tubes of one rowstaggered with respect to the tubes of an adjacent row, or the bank I!may consist of but a single row of tubes in some instances. The banks oftubes I6 and I1 and the lower and side walls of the setting I! form aboiler or saturated steam furnace chamber l8 which is fired by aplurality of fluid burners l9 which may burn pulverized fuel, gas or oilor a combination of such fuels, to provide a stream or a plurality ofstreams of products of combustion in the furnace chamber. In thearrangement shown, the burners I! are disposed in a side wall of thesetting and fire substantially parallel to the axes of the boiler drums.These burners may be disposed in any other convenient location. In someinstances a single burner l9 may sufllce.

A superheater furnace 20 in the setting I2 is defined by the tubes II,the front, side and upper walls of the setting and the drum I3. Asuperheater is disposed in the furnace 20 and in the form shown in Fig.1 consists essentially of headers 2|. and 22 supported on the setting,and a plurality of loop tubes 23 connecting these headers, th tubesbeing arranged in a single row and being disposed along the front andupper walls of the setting, adjacent the drum I3 and adjacent the tubes11. It will be understood that the superheater tubes may be arranged ina plurality of spaced, parallel rows if desired, with the tubes of onerow staggered or in line with the tubes of an adjacent row. Any othertype or form of superheater with the tubes thereof suitably placed maybe ;used in lieu of the form disclosed in Fig. 1. A steamline 24connects the upper portion of the steam and water drum It with thesuperheater inlet header 2|. The superheater furnace 20 is fired by aplurality of fluid burners 25 which are disposed, as shown, in the sameside wall of the setting as the burners I9. In some instances a singleburner 25 may suflice. A gas outlet 26 extends from the rear of thesetting adjacent the rear wall 21 and connects with a stack 28. In theform shown, the gas outlet is not controlled by dampers or the like. Aneconomizer 29 or other heat recovery device, is disposed in the fiue 20but may be omitted, if desired.

During operation of the form of generator heretofore described, if a lowdegree of superheat only is desired, one or more of the burners l9 arefired and the burners 25 are not operated. The one or more streams ofproducts of combustion or I l I gases so produced flow through thefurnace l8 and over the tubes l and out through flue 25 over theeconomizer 23 to the stack 28. Some of the gases also flow over or incontact with the tubes I1 and a comparatively small quantity of thesegases will pass over those portions of the superheater tubes which aredisposed adjacent the tubes I1, and since comparatively little of theheat radiated from the gases reaches the superheater tubes, the steampassing through the superheater will be superheated only to a smallextent. On the other hand, if a high degree of superheat at low loads isrequired, one or more burners 25 is or are operated and the burners l3are not operated. Under these circumstances, the gases so produced willflow through the superheater furnace 20, over the portions of thesuperheater tubes adjacent the bank l1, over the tubes ll, throughfurnace l8, over the tubes l5 and out through flue 25 and stack 28. Inother words, all the gases produced in the superheater furnace flow overall the steam generating tubes and give up heat to produce saturatedsteam. For other operating conditions, both the boiler and superheaterfurnaces l8 and 20 respectively, may be fired at the same time and thenumber of burners l9 and burners 25 in operation at any time as well asthe intensity with which the burners are fired will depend upon the loadon the generator and the required degree of superheat of the steam.Saturated steam may be withdrawn through outlet connection 30.

Figs. 3 and 4 illustrate an arrangement for separately controlling thesupply of air to the burners l9 and 25 which fire the boiler furnace andthe superheater furnace respectively. It is well known that the rate atwhich heat is given up to heating surface exposed to the radiation of aflame increases as the rate of firing increases and decreases as theratio of airto fuel increases. This principleis employed in thearrangements shown in Figs. 3 and 4 with a steam generator embodying theinvention, to vary the degree of superheat. In the arrangementdisclosed, the setting 3| has its four vertical walls surrounded by awind box 33. Air under pressure is introduced into the wind box at therear of the setting and flows throughout the wind box to the partthereof which is disposed outside of the front wall 34 ofthe setting inwhich the burners l9 and 25 are located. In the form shown, downcomers35 connect the upper drum l3 and the lower drum l4 and downcomers 36connect the upper drum and the lower drum l5.

- These downcomers are disposed in the wind box 32 so that they are in atemperature zone which is considerably lower than that of the boiler andsuperheater furnace; As shown, the number of downcomer tubes connectingthe drums l3 and I4 are greater than the number connecting the drums l3and I5, but the number of downcomers in each group may be varied toobtain the results desired. It will be understood. however, that the useof the downcomers heretofore mentioned is not essential to the operationof the generator, and that they may be omitted if desired. The group ofburners I9 for firing the boiler furnace is surrounded by a metalliccasing or closure 31 which extends between the front wall 34 of setting3| and the casing 33. A similar enclosure or metallic casing 38surrounds the superheater burners 25. Each casing 31 and 38 is providedwith a plurality of openings each of which is controlled by a damper 39.The casing 31 is provided with an opening in each of the five sidesthereof, whereas the casing 38 is provided with similar air openings inonly three sides thereof, but if the constructional arrangement permits,there may be damper controlled openings in each of the sides thereof.

One of the dampers 39 and the operating means therefor is shown ingreater detail in Fig. 5 of the drawings. The damper 39 is mounted atboth ends so as to swing or oscillate about its longitudinal axis and toengage the spaced stops 40 and 4| when it is in closed position. A lug42 having spaced upstanding ears 43 between which extends a pin 44 isfixed to one face of the damper 39 in a position midway of the ends ofthe damper but with pin 44 at one side of the longitudinal axis thereofas clearly shown in Fig. 5. A bolt 45 has a head 46 on one end with aslot 41 through which passes the pin 44. The other end portion 48 of thebolt is threaded and carries a nut 49 fixed to the operating hand wheel50. Nut 49 is held in position by split cap 5| which is bolted toflanged sleeve 52 which in turn is secured to the casing 33 of the windbox. A stop collar 53 is carried on bolt 45 in such fixed position thatit engages the inner end of sleeve 52 when the damper is in fully openedposition as indicated in dotted lines in Fig. 5. The outer end of thebolt- 45 carries a pin 54 which moves in a slot in a sleeve 55 toindicate the position of the damper. The sleeve 55 adjacent the slot maybe calibrated to indicate the degree to which the damper is opened orclosed. Damper operating means other than that disclosed may be utilizedif desired. With this or an equivalent arrangement, the amount of airsupplied to the burners l9 and 25 may be separately controlled andregulated as desired to obtain the combustion conditions required. Inthis manner, the degree of superheat may be readily controlled byoperation of .the dampers without changing the rate of supply of fuel tothe burners in either of the furnaces. For example, if air is suppliedto the burners in both furnaces at a. constant pressure and it isdesired to raise the superheat without varying the relative rate ofsupply of fuel to the burners or to the furnaces, this may beaccomplished by partially closing the dampers which control the supplyof air to the burners for the superheater furnace which will increasethe temperature in the superheater furnace and thus result in anincrease in the superheat. Or, if both furnaces are running with alldampers wide open and a lower degree of superheat is -desired, thedampers surrounding the burners is are partially closed thus increasingthe air pressure in the wind box 33, more air is supplied to thesuperheater furnace, and the superheat is lowered. Conversely, if ahigher superheat is desired, the dampers surrounding the superheaterfurnace burners 25 are partially closed, less air is supplied to thesuperheater burners and the superheat is raised.

In marine installations, when closed stokeholds are used, a wind box orthe equivalent need not be employed. In such instances the supply of airto the burners l9 and 25 may be controlled by enclosing the burnerssimilarly to the manner described with one or more dampers to controlthe supply of air into the enclosure and thence to the burners.

With the arrangement herein disclosed, it will be percelyed thatanextremely compact steam generating and superheating unit has beenprovided which possesses great flexibility of control of the productionof superheated steam of the desired degree of superheat at all rates ofsteaming. Great economy and emciency are provided due to the flow overthe steam generating elements of the unit of all products of combustiongenerated in the superheater furnace.

Although a preferred form of the invention has been disclosed, theprinciples of the inven' tion may be embodied in other forms of generat'ing and superheating units.

Various changes may be made in the forms of the several parts orfeatures of the generators herein disclosed, and in their relativelocation and arrangement without departing from the principles of theinvention. Accordingly, the invention is not to be limited excepting bythe scope of the appended claims.

What is claimed is:

1. A vapor generator comprising a setting, vapor generating tubes in thesetting, a boiler furnace in the setting, fuel burner means for firingthe boiler furnace, a superheater in the setting outside of the boilerfurnace, separate fuel burner means for firing the superheater, meansfor separately supplying fuel and air to the superheater firing means, agas outlet for the setting so located that the gases produced in thesuperheater furnace flow into the boiler furnace and over the vaporgenerating tubes prior to flowing into, the gas outlet, means forvarying the quantity of air supplied to the superheater firing meanswhile maintaining substantially constant the quantity of fuel suppliedthereto to control the degree to which the vapor is superheated, andmeans for varying the quantity of air supplied to the boiler furnaceburner means.

2. A vapor generator comprising a. setting, vapor generating tubes inthe setting, a boiler furnace in the setting, one or more burners forfiring the boiler furnace, a superheater in the setting outside of theboiler furnace, one or more burners for firing the superheater, meansfor separately supplying fuel and air to said burners, a gas outlet forthe setting so located that the gases produced in the superheaterfurnace flow into the boiler furnace and over the vapor generating tubesprior to flowing into the gas outlet, means for separately enclosing theone or more burners for firing the furnace and the one or more burnersfor firing the superheater to prevent access of air thereto, and meansfor separately controlling said enclosures to vary the quantity of airsupplied to said burners, the arrangement being such that the degree towhich the vapor is superheated is varied by varying the quantity of airsupplied to the burners for firing the superheater while maintainingsubstantially constant the quantity of fuel supplied thereto.

3. A vapor generator comprising a setting, vapor generating tubes in thesetting, a boiler furnace in the setting, one or more burners for firingthe boiler furnace, a superheater in the opening in each casing throughwhich air is Supplied to the burners therein, and a damper forcontrolling each opening to thereby control the quantity of air suppliedto said burners, the arrangement being such that the degree to which thevapor is superheated is varied by varying the quantity of air suppliedto the burners for firing the superheater while maintainingsubstantially constant the quantity of fuel supplied thereto.-

4. A vapor generator comprising a setting, vapor generating tubes in thesetting, a boiler furnace in the setting, one or more burners for firingthe boiler fumace; a superheater in the setting outside of the boilerfurnace, one or more burners for firing the superheater, means forsupplying fuel to said burners, a gas outlet for the setting so locatedthat the gases produced in the superheater furnace flow into the boilerfurnace and over the vapor generating tubes prior to flowing into thegas outlet, an air casing outside at least one wall thereof, anenclosure in the air casing for enclosing the one or more. burners forfiring said furnace, an enclosure in the air casing for enclosing theone or more burners for firing the superheater, each enclosure havingone or more openings therein through which air from the casing entersthe enclosure for the burners therein, and a damper for controlling eachof said openings to vary the quantity of air supplied to each enclosureand the one or more burners therein, the arrangement being such that thedegree to which the vapor is superheated is varied by varying thequantity of air supplied to the burners for firing the superheater whilemaintaining substantially constant the quantity of fuel suppliedthereto.

5. The method of generating and superheating vapor which comprisespassing liquid through a vapor generating zone, supplying fuel and airto a combustion zone for the vapor generating zone, passing vapor fromthe vapor generating zone through a superheating zone, suppling fuel andair to a superheater combustion zone, causing the gases produced in thesuperheater combustion zone to flow into the combustion zone prior toflowing through the vapor generating zone, controlling the degree towhich the vapor is superheated by varying the quantity of air suppliedto the superheater combustion zone while maintaining substantiallyconstant the quantity of fuel supplied thereto, and controlling thequantity of air supplied to the combustion zone for the vapor generatingzone.

JOHN BLIZARD.

